No large-scale study within the United States has examined any aspect of the epidemiology of intracranial meningiomas, a lesion which accounts for up to 25% of all primary intracranial neoplasms. We propose to conduct a population-based case/control study of meningioma within the states of Connecticut, Massachusetts, North Carolina, and Texas as well as the San Francisco Bay area under the mechanism of an integrated R01 (Note that identical applications are submitted for all five sites). Cases will be selected using rapid case ascertainment and will include all male and female individuals diagnosed with a histologically confirmed intra-cranial meningioma between the ages of 20 and 79 years from 7/1/2006 through 6/30/2010 in the above listed regions. Control subjects will be identified via random-digit dial methods and matched to the cases by sex, ethnicity, geographic location, and five-year age category. Study subjects will be administered a telephone questionnaire to collect information on the two primary categories of risk, exposure to ionizing radiation and hormones as well as additional risk factors such as family history of meningioma and other tumors, cell-phone utilization, and head trauma as well as questions on outcome and quality of life. Parraffin-embedded tumor tissue blocks will be obtained for case subjects to allow for 1) a uniform histological review, and 2) immunohistochemical testing for estrogen, progesterone, androgen and MIB-1 receptors. Blood or buccal specimens will be collected from all study subjects for testing of DNA polymorphisms in DNA repair and cell cycle genes. This study represents the first concentrated effort to examine environmental and genetic risk factors for meningiomas.